Assos Women's Uma GT Ultraz Winter Jacket Evo review: exceptional but not for curves

For a deep winter’s jacket you need high levels of insulation, limited bulk and exceptional breathability to keep you happy and comfortable hour after hour in the saddle. The Assos Uma GT Ultraz Winter jacket Evo has this in spades, holding its own in our guide to the best winter cycling jackets. 

That the Assos Uma GT Ultraz Winter jacket Evo is so well made is no surprise. Assos jackets are built for specific conditions and specific purposes. It feels like a serious, grown up jacket, for serious, grown up cyclists. It even has a lapel telling you exactly what its Unique Selling Points (USP) are and how to wear it (as part of a layering system), and a sleek cyclist-looking shape to it. Everything about this jacket seems to scream high quality and performance. 

In order to test it, I decided to take the jacket out in as many weather conditions as possible, which was a great plan as this autumn and winter in Britain seems to have given us every season imaginable. We've seen unseasonably warm days. We've seen days with brutal winds, we've seen cold, dark, and damp days, and we've even seen some bright clear icy days. In particular, I adopted this for most of my morning commutes, where I needed something visible, warm and able to cope with changeable conditions. 

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Design and Aesthetics

Despite my raving about Assos' carefully considered designs, sizing turned out to be incredibly difficult on the Assos website, and I chose poorly. I went for a small, but should have sized up to a medium, if not a large. ASSOS says that the Uma GT Ultraz jacket Evo is a more relaxed fit, but that isn’t at all what showed up on my doorstep. Instead, I received a race-style, second skin cut that isn't my personal preference at all in a jacket. Assos recommended a small size based on my age, height and weight, and as there was no additional size guide to scrutinise that assumption, I went with their recommendation.

Consequently, I spent a lot of time tugging this jacket to get it to sit in place; with a longer torso, smaller waist but larger bust than typical for my smaller frame, I felt a bit like I was trying to fit myself into doll’s clothes, made for perfectly proportioned women rather than the curvier human shape I am. The torso was too short for me, arm holes too small and the fabric constricted my chest. Even zipping it up from my hips was a struggle, the thick elastic waistband that keeps the garment in place was so effective that I almost had to wrestle the zip together. 

Regardless of the sizing though, there is no denying that this is a well crafted and considered jacket, and I must give credit where credit is due. The Uma GT Ultraz jacket front panel is constructed of 3 layers with a Polyurethane bonded membrane for 100% windproofing and high levels of insulation. Inside, Assos has structured the jacket with two fleecy panels across the chest, and the back panel constructed from a structured fleece RX material, which has the look and feel of corduroy. The sleeves are a lighter, softer material which adds to the ventilation. 

The craftsmanship is superb, and constructed with over 50% Nylon Polyamide, a material well known for its shape retaining, durability and colour staying properties, the jacket is going to last a very long time. Even the stitching feels clever and durable, with no annoying seams poking you in the side. 

My favourite part of the jacket though was the pockets on the rear. They were just so well made, with tons of room to fit all manner of snacks, bottles and valuables, but with a sort of double stitching over the top that partially sealed the pockets once the jacket was on. I love having stuff quickly available to me on a ride, I don’t want to faff about with zips, especially in the winter. 

I chose the lurid fluoro yellow colourway for this test, wanting to try a jacket that actually felt visible. I was a bit disappointed that Assos has only kept the bright colours on the front panels, opting for black with two reflective strips on the pockets on the back, which I felt ruined the visibility. Aesthetically, I know this was a better choice, and probably looks more sleek-cyclist than health-and-safety official, but I’m slightly more concerned about being visible from behind than in front. 

Performance

Assos states (on their USP lapel) that this jacket is effective at temperatures between -4 degrees celsius and up to 8 degrees celsius. I trailed this jacket in as many different weather conditions as I could, finding that it was particularly great on windy, cold, overcast drab days that constantly threatened showers. Perfect for 90% of British winter. As mentioned above though, you can't fit layers under this and limits how low you can go. For me anything lower than around 3 C / 37 F wasn't super comfortable. On the other hand, due to the cooling strategies it did mean that I was still comfortable nearing almost 10 C / 50 F, making it a fairly versatile jacket across the seasons. 

While the Uma GT Ultraz jacket is water repellent rather than fully waterproof, it is really very good at repelling water. I’ve had waterproofs that are less effective at preventing me from getting soggy than the this one. Even in quite heavy downpours, it took much longer for the rain to soak through than in other jackets, and the odd shower here and there barely bothered it.  It also dried super fast, which was great. Assos has paired this water repellent quality with high levels of insulation. Though heavier than jackets such as the Rapha Women’s Explore Down jacket I tested, the insulation is still exceptional in its warmth retention without the additional bulk. With just a thermal jersey beneath it, I felt fairly comfortable on most of my winter rides, and I’d be interested to see how much better it performs as part of the recommended layering system with an Assos Women’s Winter LS Skin beneath it.  

Breathability was second-to-none too. One of my favourite jackets of this season has been the Endura Women’s Pro SL Primaloft jacket, mainly for its clever ventilation strategies and for keeping me cool, and the Assos jacket did a similar thing, but with the flexibility of wearing it over lower temperatures. This meant that I could really push hard up hills or on the flat without getting overly hot and sweaty, and then as I backed off the session and cooled down I didn’t start getting chilly. My body temperature stayed comfortably consistent, even over a longer ride in damp weather, where ordinarily I’d end up getting colder and colder until I’m an ice block and desperate for a warm shower. The back panel and sleeves did most of the work here, allowing excess body heat to channel straight out. Unlike the Endura jacket though, this worked to ensure I’d be comfortable at much lower temperatures. 

For me though, the windproofing was where this jacket really shone. A jacket that can block out most of the windchill is largely going to be more impactful than lots of insulation, and the Uma GT Ultraz jacket does a good job of blocking out the worst of it. Even on fast descents, with the wind stinging my face and making my eyes water, I stayed perfectly warm. This was even more noticeable because it helped keep my fingers warm in my gloves (the warmer your core, the warmer your hands). 

I’ve already mentioned that the fit wasn’t quite right on me, and so riding wasn’t exactly the most comfortable. The droptail didn’t drop far enough down and the elasticated banding kept riding up further up my back than I’d like, as did the torso, which felt much too short and seemed to want to bunch up under my belly button. I recognise though that not everyone will have these issues with the fit, and so being objective, the front panel fabrics with 2-way stretch do allow natural movement, and the thick bands should keep the jacket in place on longer rides. The two way zip is chunky and well made, and the toggle was big enough for me to grab with gloves on, and the collar sat high enough to not need a buff. I’d argue that it was slightly too high for me (I'm sensitive to chin guards aggravating my skin), but it did keep water and wind off my chest. 

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Verdict

The Assos Uma GT Ultraz Winter jacket Evo is not a cheap jacket, and definitely sits very much on the side of ‘investment piece’. It’s an exceptionally well crafted and carefully considered item, perfectly made for superior warmth and breathability on the bike. It does these things incredibly well, and I wish I loved the fit as much as I liked how well it performs. 

Unfortunately though I just didn’t find myself reaching for it in the same way I did with the Assos Uma GT Jacket, which is a shame, because objectively I know it was one of the better performing items I have tested and would have kept me dry, warm and visible on many rides. It’s the perfect year-rounder jacket too, effective I’d imagine, all the way up to spring; I’d just recommend sizing up a couple of sizes if you’re a bit curvier.